重医大临床麻醉学教案10椎管内麻醉.docx

授课教案课程名称临床麻醉学年级授课专业麻醉学系教 师职称授课方式大课学时4题目章节第十章椎管内麻醉教材名称根据临床麻醉学椎管内麻醉章节 改编为英文作者房秀生，刘新伟出版社版次第一版教 学 目 的 要 求1 .蛛网膜下腔阻滞：熟悉腰麻的作用机理及其对生理的影响。掌握腰麻的适应证，禁忌 证与并发证。熟悉腰麻的平面调节和用药基本方法。了解穿刺要点。2 .硬膜外阻滞。熟悉硬膜外阻滞的作用机理及其对生理的影响，掌握硬膜外麻醉的适应 证，禁忌证，平面调节和麻醉管理。理解其穿刺要点，注药方法，掌握硬膜外麻醉的 并发证。教学难点1 .椎管的解剖，穿刺层次，注药部位。2 .椎管内麻醉对生理的影响。3 .影响腰麻平面的因素及平面的调节。4 .术后头痛的原因与处理。5 .硬膜外麻醉注药原则6 .全脊椎麻醉的产生与预防，处理。教 学 重 点1 .椎管的解剖，穿刺层次，注药部位。2 .腰麻与硬膜外麻醉对生理影响。3 .腰麻与硬膜外麻醉的适应证与并发症。4 .腰麻与硬膜外麻醉的区别外语 要求掌握椎管内麻醉章的英文关键词，能基本听懂全英文讲课，血rathecal anesthesia; epidural anesthesia; spinal anesthesia; cerebrospinal fluid (CSF).学法段 教方手讲授及多媒体教学。经考 资料1. Clinical anesthesiaBy GE.Morgan.2. (Textbook of anesthesia教研十.届、同意教学组长：教研室主任：20年 月 日Steps:A. Keeping the airway patency, maintainingadequate ventilation and giving oxygen.B. Supporting circulation :Infusion of intravenous fluids quickly.Use vasopressors by IV .C. If cardiac arrest occurs, CPR must be immediately performed.Prevention of TSAstrictly using the test dose of local anesthetic, aspiration the catheter before injection . carefully observing patient after injectedlocal anesthetic .Toxic reactionReasonsintravascular injection.absorption of excessive amounts of anesthetic.Clinical characteristicsnumbness or tingling of tongue tinnitus, lingual sensations & light headed.consciousness lost.convulsion.PreventionlOminlOminaspirating the needle or catheter, using test dose.observing early signs of toxicity.Managementoxygen inhale patency air way. sedative & anti-convulsion agents, keeping circulation stable.4. HypotensionManagement crystalloid or colloid solution. IV Infusionephedrine 15-30mg IV. atropine 0.25-0.5mg IV. Oxygen inhale.Nausea or vomitingReasonshypotensionlOminlOminvisceral manipulationhypoxemiaManagementincrease fluid transfusion inhale oxygendrug usage: atropine, efedrina, antiemetics.Respiratory depressionReasons high level of epidural anesthesia.Clinical signs SO2% decreased, tidal volume decreased, or apnea. Managementavoid high block level. decrease anesthetic drug concentration. oxygen inhale & respiratory support.Postoperative complications1. HeadacheReasonfollowing dura tap.Managementlying in bed. liquid infusion. sedative & analgesia agents. epidural blood patch.2. Neurologic injuryReasons Puncture trauma to spinal root, nerve fibers or spinal cord. nerve injury result from the direct effect of local anesthetics . ManagementPrevention. Consulatation neurologic physicianEpidural hematomaReasonbleedingabnormal coagulation or disorder puncture trauma.Managementpost-operation patient visiting. choose indication patient. perfect puncture technique.3. Epidural abscesslOminlOminReasonspuncture site infectious. unsterilized epidural pack. practitioner unsterilized performance. Managementantibacterial agents. decompression of laminectomyIndications and contraindicationsIndications operation of chest wall. major abdominal operation . gynecology and obstetrics. lower extremity surgeryurologic surgery ContraindicationslOminlOmin patient refusal. local infection at the site of puncture. severe hemorrhage or shock. severe hypovolemia. coagulopathy or anticoagulant therapy. severe cardiovascular diseasespreexisting neurologic diseases septicemia.Differentiation between Spinal& Epidural AnesthesiaEpiduralC-S epidural Large upper & lower Singe & Continuous with catheterpuncture sit injection space Dosage block Pattern injectionSAB<L2 subarachnoidsmallTransectionSingle小结思考 题及 预习预习1 .硬膜外麻醉与腰麻对身体的生理影响？2 .硬膜外麻醉与腰麻的相同点与不同点？3 .椎管内麻醉后头疼的机制与预防，处理。4 .椎管内麻醉的适应症与并发症。复合麻醉与联合麻醉.通过学习椎管内麻醉，复习椎管的解剖，掌握腰麻与硬膜外麻醉的穿刺部位，穿刺 层次。1 .学习椎管内麻醉对身体的生理影响。2 .掌握腰麻的用药，麻醉平面的调节，并发症与适应证。腰麻后头痛的预防与处理。3 .掌握硬膜外麻醉的注药方法与意义。麻醉平面的调节。术中与术后并发症。全脊椎 麻醉的预防与临床表现与处理。4 .熟悉腰麻与硬膜外麻醉的比较。教学内容辅助手段时间分配多媒体lOmin多媒体lOminIntrathecal AnesthesiaIntrathecal anesthesia.Intrathecal anesthesia result in sympathetic block, sensory analgesia, and motor block (depending on dose, concentration, or volume of local anesthetic) by local anesthetic is injected into subarachnoid space ( spinal anesthesia ) or the epidural space (epidural anesthesia ) and bathes the nerve roots in the subarachnoid space or epidural space, respectivelyIntrathecal block is divided into two classesSubarachnoid block (spinal block): Local anesthetic is injected into subarachnoid space.Epidural block: Local anesthetic is injected into the epidural space.AnatomyVertebral column 7 cervical (C),12thoracic (T), 5lumbar (L),5sacral (S) fusedas thesacrum, 4small coccygealvertebra(Co) that form the coccyxlOminVERTEBRAThe vertebral arch encloses the vertebral foramen, each vertebral arch has two parts, that is pedicle (root) and lamina. Pedicles have large notches on their inferior surface and smaller notches on their superior surface. Notches from adjacent vertebrae form intervertebral foramina, through which nerve roots exit the spinal column.Sacrum & Coccyx:The sacral hiatus leads into the sacral canal, the inferior end of the vertebral canal .Ligamentum of vertebral columnSupraspinous ligament Interspinous ligamentLigamentum flavum(the yollow ligament)Spinal cordspinal cord extends from the foramen magnum to the level of LI in adults.The anterior and posterior nerve roots at each spinal level join one another. Cauda equina( horse's tail).Spinal meninges spinal cord7 spinal dura materarachnoid mater8 一 spinal pia materSpinal space Epidural spaceSubdural space Subarachnoid spaceSpinal nerves dermatomic distributionT2manubrium of sternumT4 -nipplT6 -xiphoid processT8 -between T6 & T10T10 navelT12 pubic symphysisPhysiologic Effects of Intrathecal AnesthesiaNerve blockade sequenceSympathetic - sensory - motor - sheathed nerve.Differential nerve blockade levelSympathetic blockade that may be two segments level higher than the sensory block, which in turn is two segments higher than the motor blockade.Respiratory system1. Low spinal block or low epidural block2. Motor blockade extending to the roots of3. High thoracic level blockade can causeis a marked decrease in vital capacity.Cardiovascular system1. Decrease blood pressure .2. Reduction in cardiac output and cardiac3. Bradycardia.( block T1 -T4 ).Gastrointestinal system1. Increase intestinal contraction.2. Nausea, retching or vomiting:has no effect on the respiratory system, the phrenic nerves(C3-5)causes apnea, loss of intercostal muscle activity, therecontractility.lOminSpinal Anesthesia(spinal block or subarachnoid block, SAB)SAB is a type of regional anesthesia, which is achieved by injecting a local anesthetic into the lumbar subarachnoid space.The term for SAB levelBlock level higher T4 is high level SAB Block level lower T10 is low level SABBlock region only cover the perineum & buttock is saddle block Block only occur in unilateral lower extremity is unilateral block.lOminLocal anesthetics for SABSolution baricity :(The specific gravity of CSF is 1.003-1.009 at 37.)Hyperbaric solutionAddition of glucose 5% or 10% to a local anesthetic solution produces a solution with specific gravity of 1.024 or greater, this solution is heavier than CSF A hypobaric solutionLighter than CSF, it can be made by the powder anesthetic plus of sterile water or the pure anesthetic solution.1. An isobaric ( plain ) solution ;Anesthetic agents are mixed with CSF.Local anesthetic solution:(hyperbaric with epinephrine)Procaine 5% solution + 5% glucose.Dosage:100-150mg. Duration: 45-90min Tetracaine 1% solution 1 ml +10% glucose 1 ml + 3% efedrina 1mL (1+1+1 solution).Dosage: 10-12mg .Duration : 120-240minBupivacaine 0.75% solution + 5-10% glucoseDosage: 10-15mg.Duration: 100-150minlOminlOminVasoconstrictorsEpinephrine & phenylephrine Both agents appear to decrease the uptake and clearance of local anesthetics from CSF. Addition of vasoconstrictors in local anesthetic solution can prolong the duration of spinal anesthesia.Dosage: Epinephrine(0.1-0.2mg).Assessing blockade level: The sensory level of blockade can be assessed with pinprick or ice, the level of sympathectomy is assessed by measuring skin temperature.The complete block of motor nerves is manifested inability to move thelegs or foot.Factors affecting spread of hyperbaric1. spinal solutionPatienfs position "saddle block keeping the patient sitting for 3-5 minafter injection of l-2ml of hyperbaric solution .lateral position. unilateral blocks keeping the patient onDrug dosage & solution volume 3.4.5.Speed of injection.The rate of injection is 1ml / 5 sec.Lumber puncture site.Needle bevel direction.SAB level management (Hyperbaric solution) Complications of SAB1. HypotensionReasons: vessels dilatation; increased blood pooling; decreased return to heart. Cardiac contractility decreased.bloodflowlOminAugmented by:HypovolemiaChanges in positionBradycardiaTreatmentfluidsPrevention: Use of crystalloid or colloid10-20ml/kg for volume10-20ml/kg for volumeloading pre-lumber puncture.Increase fluid administration. Mask oxygen inhale.Drug: Ephedrine 10-15 mg IV. BradycardiaReasons:block the cardiacSpinal block level higher than T4 , which may sympathetic accelerator fibers (Tl- T4),then bradycardia may occur.SAB does not block the vagal nerve. Unopposed vagal tone increased is another reason for bradycardia.TreatmentAtropine 0.25 - 0.5 mg iv. Ephedrine 15-30 mg iv.Nausea and vomitingReasons increased vagal tonehypotension Operation explorationHypoxemiaTreatment: Check BP & HRlOminlOmin Atropine 0.25-0.5 mg. iv . Ephedrine 15 mg - 30 mg. iv. Mask oxygen inhale4.Headache (post -dural puncture headache, PDPH) The incidence rate is about 20-30% . Headache may occur after dural puncture, presumably secondary to the tear in the dura and that result from decreased intracranial pressure as CSF leak from the dural defect, which may cause traction on the meninges and cranial nerves.Clinical characteristicsThe onset time in 12-72 hours. persist for up to 1-6 weeks. The headache is aggravated by sitting or standing. Relieved or lessened by lying down flat. Treatmentkeeping recumbent position. intravenous or oral fluid administration. epidural blood patch treatmentlOminlOmin a saline bolus epidural space injectionsedative & analgesic agentUrinary retentionReasons Block of S2-S4 root fibers decreases urinary bladder tone and inhibits the voiding reflex. Associated with the surgical procedure. Urinary retention is usually temporary. Persistent bladder dysfunction may be a serious neural injury.Treatment: a urethral catheter inserted Neurologic complicationsCauda equina syndrome MeningitisArachnoiditis Cranial nerve palsy Indications & Contraindications Indications lower abdomen operation. perineum operation. lower limbs operation.ContraindicationsInfection at the site of puncture. Bleeding diathesis or coagulopathy. Severe hypovolemia. Severe cardiovascular diseases. Severe spinal deformity. Preexisting neurologic diseases.lOmin Intracranial high pressureEpidural Anesthesia Concept Epidural anesthesia is achieved by injecting a local anesthetic into the epidural space , which blocks the spinal nerve roots, producing regional anesthesia.Epidural block methodsa single-shot injective techniques. a continuous infusion & intermittent bolus techniques.lOmin“A catheter insert to the epidural space for continuous infusion or intermittent bolus injection.”Epidural anesthetic agents1. Lidocaineshort - to intermediate-acting agent.concentration of 1.5-2.0% with adrenaline 1:200,000.anesthesia duration 90 -150 min.total dosage limited 400mg in adult.2. Bupivacaine long-acting local anesthetic. used in 0.5% or 0.75% with adrenalin 1:200,000. onset time is 10 -15 min duration is about 200 -260 min. dosage limited 150mg in adult.3. Ropivacaine new amide local anesthetic with a less cardiac toxicity than bupivacainelOmin slow onset time and long anesthesia duration. use 0.5 % or 0.75% withl:200,000 or without adrenalin. Dosage limited 150 -200mg in adultAdministration of local anestheticThe quantity of local anesthetic need for epidural anesthesia is relatively larger compared with spinal anesthesia. Significant toxicity can occur if this amount of anesthetic is injected subarachnoid space or intravascular. Safeguards are the epidural test dose and incremental dosing (or main dose). Test doseAim : to detect whether subarachnoid injection to detect whether intravascular injectionMethod: 3 - 4ml of 2% lidocaine with 1:200,000 epinephrine(5ug/ml) is injected to epidural space, if injected into subarachnoid space, that will produce spinal anesthesia rapidly. The 15ug-20ug of epinephrine, if injected intravascularly, a noticeable increase in heart rate produced. Incremental doseIncremental dose is a very effective method of avoiding serious complication. After 5min of test dose given, there is no system toxicity & no signs of spinal anesthesia occurs then the incremental dose can be injected into epidural space.Factors affecting blocking level of anesthesia1. Volume:in adults, 1 -2 ml of local anesthetic per segment to be blocked is a generally accepted guideline.For example, to achieve a T4 sensory level from an L4 -L5 injection would require about 12 -24 ml.2. Age:The dose required to achieve the same level of anesthesia decreases with age. This is probably a result of age-related decreases in the size or compliance of the epidural space. So the older patients requires less local anesthetic.3. Height: The patient height affects the extent of cephalad spread. Thus the shorter patients may requires only 1ml of local anesthetic per segment to be blocked, while the taller patient generally requires 2ml per segment.4. Pregnancy: Requires less volume of anesthetic. Because the epidural space venous dilatation and it is pressure increased by pregnancy, it is augmented the anesthetic spreading wider.Puncture siteHigh level epidural block (C5-T6 ). Middle level epidural block( T6-T12 ). Low level epidural block( LI-). Caudal block.Failed epidural blocksmisplaced injectionlOmin unilateral blocksegmental sparing visceral painComplicationsIntraoperative complicationsDural tap The epidural needle puncture the dura mater &subarachnoid mater and enters into subarachnoidspace.It can berecognizedby free flow of CSF drips from theneedle. An epidural catheter might puncture the dural.Total spinal anesthesia (